Operating mechanism for grabs



Nov. 1, 1949. P. J. M. T. ALLARD 2,486,544

OPERATING MECHANISM FOR GRABS Filed March 16, 1946 3 Sheets-Sheet 1 PnuiRE Suva-Mame HEoDoae AL R ENTQR W 3 iW'TE,

,Nov. 1, 1949.

P. J/M. T. ALLARD OPERATING MECHANISM FOR GRABS 5 Sheeis-Sheet 2 Filed March 16, 1946 R EERE. XE: MAmaTuowae N-mmo \NVENTOK.

Nov 1, 1 P. J. M. T. ALLARD OPERATING MECHANISM FOR GRABS 3 Sheets-Sheet 3 Filed March 16, 1946 \NvENToR m WM A ATTV,

Patented Nov. 1, 1949 OPERATING MECHANISM FOR GRABS Pierre Jean Marie Theodore Allard, Chantilly,

France, assignor to Societe Francaise de Construction -de Bennes Automatiques,

(Seine-ct Oise), France Application March 16, 1946, Serial No. 654,926 In France January 20, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires January 20, 1965 Claims. (01. 3711s) The invention relates to mechanisms for opening and closing grabs of the type comprising two jaws pivoted by separate pivots on a central casing and the opening and closing movement of which are efiected by means of two groups of dif--- ferent cables.

The mechanism according to the invention comprises a drum of large diameter on which is wound the group of closing cables and, for each closing cable, a drum of small diameter connected to one of the satellite pinions of an epicycloidal train comprising an inner planet wheel integral with the axis of the drum of the closing cable and a crown or outer planet wheel connected with the central casing, the pinion carriers of this train being connected to one at least of the jaws.

According to another feature, the pinion carrier is connected to the two jaws by rods of suitable form.

According to a further embodiment, the. pinion carrier is connected directly to one of the jaws which comprise a toothed sector meshing with a corresponding sector of the other jaw.

Other features of the invention will appear from the following description with reference to the annexed drawing which shows, by way of example, an embodiment of the invention, and in which:

Fig. 1 is an elevational view of a grab provided with the arrangement according to the invention.

Fig. 2 is a section of the operating device on the line 2-2 of Fig. 1.

Fig. 3 is an elevational view of the operating means, the grab being in closed position.

Fig. 4 is a view similar to that of Fig. 3, with the grab in open position.

Fig. 5 is a view in section of another embodiment of the arrangement according to the invention.

Fig. 6 is a view similar to Fig. 5, showing the grab in open position.

Referring to Figs. 1 to 4, l and 2 indicate the jaws of the grab pivoted at 3 and 4 to a central casing 5. On the casing 5 are fixed two brackets 6 provided with bushes I serving to support a shaft 8 connecting the two brackets. On the shaft 8 is threaded a sleeve 9 secured to a drum ll] of large diameter on which are wound the cables ll serving to effect the closing of the grab. The sleeve 9 comprises at its two ends two pinions l2 each meshing with three satellite pinions l3,-

l4 and I5 of an epicycloidal train. Each epicycloidal train comprises also a ring or outer plan- Persan etary gear member I6 integral with a casing I'l fixed on the bracket 6 and a pinion carrier constituted by a bracket is mounted rotatably on the sleeve 9 and a bracket I9 rotatably mounted on the bush 1, these brackets l8 and I9 being connected by the pinion shafts and rigidly connected together in such manner as to form a frame movable as a whole.

One of the satellite pinions I3 is moreover integral with a pulley 20 of small diameter relative to the drum I0 and on which is hooked one of the two cables 2i intended to effect the opening of the grab. 1

Finally, the pinion carrier [8, I9 is connected to the two jaws l and 2 by two rods 22 and 23 connected at 24 and 25 and at 26 and 21 to the two jaws.

It is to be noted that the axis X-X of the shaft 8 is offset towards the left of Fig. 1 in relation to the median vertical plane of the grab and in the case where the cables I I are wound to the right of the drum ID, in order to avoid, due to the large diameter of the drum l0, considerable wear of the cable I l which is guided in the median plane by a pulley 28. The opening cables 2| are also guided in the median plane by pulleys 29.

The operation is as follows:

Assuming for example the grab is open (Fig. 4), closing is efiected in the following manner: the cables 2| are slack and the cables II are pulled which drive the drum [6 in the direction of the arrow F. The sleeve 9 and the pinions l2 follow the movement and the satellites l3, l4, l5, rolling inside the crown l6 are displaced in the same direction as the drum l6, driving in this movement the pinion carriers I8, l9 and the connecting pins 24 and 25 of the rods 22 and 23 which.

thus cause the jaws l and 2 to approach one another to the position shown in Fig. 3. In this movement, the cables 2| are wound on the pulleys 20.

The grab when closed and filled is brought over the discharge point and, by giving slack to the cables I i, it is suspended on cables 2|. Under the action of its weight, the cables 2i unwind from the pulleys 26 setting them in rotation, in order to come from the position of Fig. 2 to that of Fig. 4. In this movement, the rotation of the satellite pinions l3, l4 and [5 bearing on the crown l6 cause rotation of the pinions [2 in the direction of the arrow 1, and thus a corresponding rotation of the drum I0 and the winding of the cables ll.

It is to be noted that, due to this arrangement, the opening movement being efiected by direct action of the cable 2| on the pulley 20 is much more rapid than the closing movement, which is evidently necessary, and. that on the other hand a very important result in order to ensure. correct emptying of the grab-the length of the cable to be pulled during the: opening of the grab being small, the downward movement of the grab during opening is, consequently; also small. Fi nally, this arrangement permits. of dispensing with all the connecting members such as cablesk chains etc. between the mechanism and the aws.

In Figs. 5 and 6, is shown another embodiment in which the pivots 3 and 4 of the jaws t and 2 on the casing 5 are brought closer together.

In this case,the jaw l is directly connected to the shaft 30 of one of the satellite pinions t5 and its movement is transmitted to the jaw 2 by two toothed sectors 3| and 32 mounted on the jaws and constantly in mesh with one another. The pivot 3 of the jaw t may, asshown, coincide with the axis XX. of the shaft 8 of the mechanism.

The operation is obvious.

It wilI be understood that the invention is not limited to the details described above, which have been given only by way of example.

Having now described my invention what I claim as new and desired to secure by Letters Patent is:-

I. A grab mechanism comprising a casing; two jaws pivoted on said casing, a shaft carried by said casing, hoisting cables, a hoisting drum mounted on said shaft and adapted to receive said, hoisting, cables, an. inner planetary r member rotating with said drum, an outer planetary gear member secured to said casing, satellite pinions in engagement with said planetary gear members, a second drum integral with one of said satellite pinions, an opening cable wound W n said second drum, a pinion carrier for said satellite pin-ionsand means for operatively conmeeting said carrier to said grab jaws.

2s A swab mechanism as claimed in claim 1, further comprising means for guiding the hoisting cables in a vertical plane, the axis of the hoisting drum lying on one side of said plane.

3.. A. grab. mechanism as claimed in claim 1, in which the means for connecting the carrier to the grab jaws consists of links.

4. A grab mechanism as claimed in claim 1, in which one jaw is pivoted on the said pinion carrier and comprises toothed sectors on the jaws, in engagement with each other.

5'. A grab mechanism as claimed in claim 1, in which one jawis pivoted on the said pinion carrier and comprises toothed sectors on the jaws in engagement with each other, the said jaw being pivoted on the casing in alignment with the axis of the hoisting drum.

PIERRE" JEAN MARIE THEODORE ALLARD.

No references cited. 

